外磁系与内磁系永磁筒式磁选机对比研究

对比分析了外磁系和内磁系永磁筒式磁选机的结构、分选原理以及磁场特性，并对比了两种磁选机在铁矿石预选中的试验指标。结果表明，外磁系筒式磁选机具有独特的半闭合内敛式磁系结构，分选磁极面为凹面，分选空间磁力线局部叠加，增加了磁场强度和作用深度，磁场强度随离开磁表面的距离衰减慢; 在铁精矿品位基本相当的前提下，外磁系永磁筒式磁选机选矿回收率、选矿效率、尾矿品位均明显优于内磁系永磁筒式磁选机; 梅山铁矿采用外磁系永磁筒式磁选机的磨前预选新流程，其精矿产率、金属回收率、选矿效率分别提高了8.47、12.26和6.46个百分点。

Comparative Study on Permanent Magnetic Drum Separators with External or Internal Magnetic Systems

The structure, separation theory and magnetic field properties of permanent magnetic drum separators with external or internal magnetic systems were compared and analyzed, and their performance in iron ore preconcentration was also compared. The results show that, the magnetic drum separator with external magnetic system possesses a semi-closed and inward magnetic system, and a concave magnetic pole surface for separation, leading to the partial overlapping of magnetic field lines, which intensifies magnetic field strength and increase reaction depth. The attenuation of magnetic field strength is slowed down with the distance. For obtaining iron concentrate with almost equivalent grade, the permanent magnetic drum separator with external systems can obviously bring better pre-concentration indexes including concentrate yield, separation efficiency and tailings grade, compared with the separator with internal system. The practice of introducing the permanent magnetic drum separator with external magnetic system into the new pre-concentration flowsheet in Meishan Iron Mine shows that the concentrate yield, recovery and separation efficiency can be increased by 8.47, 12.26 and 6.46 percentage points, respectively.